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3 years ago

In the vertical columns of the periodic table, as the atomic numbers increase:

Chemistry

2 answers:

kolezko [41]3 years ago

5 0

A.) The number of electron shells increases.

Fiesta28 [93]3 years ago

5 0

Answer: a. the number of electron shells increases.

Explanation:

The elements in the vertical columns also called as groups are arranged in order of increasing atomic numbers and contain same valence electrons.

The electrons are added to new energy shells and the nuclear charge also increases due to increase in atomic number. But the effect of addition of new shells is more dominant.

As the shells increase, the atomic size increases and the valence shell moves farther from the nucleus , thus the tendency to lose electrons increase and thus the ionization energy which is the energy required to move the valence electron, decreases.

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In lab (write this down in your lab protocol), you will be given a stock solution that has a glucose concentration of 60 mg/dL.

Wittaler [7]

Answer:

1. The dilution factor for the serial dilution = 2

2. V2 = 1 mL

3. V1 = 0.5 mL

Explanation:

1. Dilution factor is the ratio of the initial concentration to the final concentration.

Dilution factor = initial concentration / final concentration

First dilution: initial concentration = 60 mg/dL

final concentration = 30 mg/dL

Dilution factor = 60 mg/dL / 30 mg/dL = 2

Second dilution: initial concentration = 30 mg/dL

final concentration = 15 mg/dL

Dilution factor = 30 mg/dL / 15 mg/dL = 2

Therefore, the dilution factor for the serial dilution = 2

2. From the dilution formula, C1V1 = C2V2; V2 = final volume to be prepared.

Since 1 mL of the various glucose solutions are to be prepared, the final concentration, V2 = 1 mL

3. From the dilution formula, C1V1 = C2V2; V1 = initial concentration of the solution to be prepared.

C1/C2 = V2/V1

Since the dilution factor, C1/C2 is 2, V2/V1 = 2

V1 = V2/2

V1 = 1 mL / 2

V1 = 0.5 mL

6 0

3 years ago

A sample of N2(g) was collected over water at 25°C and 730 torr in a container with a volume of 340 mL. The vapor pressure of wa

AnnZ [28]

Answer:

D. 0.36 g

Explanation:

When a gas is collected over water, the total pressure is the sum of the pressure of the gas and the pressure of the water vapor.

Ptotal = Pwater + PN₂

PN₂ = Ptotal - Pwater = 730 torr - 23.76 torr = 706 torr

We can find the mass of N₂ using the ideal gas equation.

$P.V=n.R.T=\frac{m}{M} .R.T\\m=\frac{P.V.M}{R.T} =\frac{730torr.0.340L.28g/mol}{(0.08206atm.L/mol.K).298K} .\frac{1atm}{760torr} =0.36g$

6 0

3 years ago

V1t2 = v2t1 is an expression of

Lesechka [4]

Answer:

v1t1 = v2t2 is Charles law

5 0

3 years ago

What is Zeff of phosphorus

professor190 [17]

Answer:

Explanation:

Here is an illustration showing how to "calculate" +5 as the effective nuclear charge (Zeff) for phosphorus. We are not implying that the electrons are in orbits here, this is simply showing inner shell electrons that shield the outer valence electrons from the full nuclear charge.

5 0

2 years ago

One acid, HA, has a pKa of 3.16 and another, HB, has a pKa of 4.14. Which is the stronger acid and why?

dezoksy [38]

PKa is defined as the logarithm of the inverse of Ka, i.e

pKa = log ( 1 / Ka)

Ka is the dissociation constant of the acid. The larger Ka the stronger the acid.

On the other hand, from pKa = log (1 / Ka) the larger Ka the smaller 1 /Ka, and so the smaller log (1/Ka).

So, the relation between Ka and pKa is inverse, which means that an acid with greater value of pKa will have lower value Ka, and so it will be weaker or the smaller the pKa the stronger the acid.

Therefore, in our case HA has the lower pKa ant it will be the stronger acid.

Answer: HA is the stronger acid, because it has the lower pKa and pKa is inversely related to the strength of the acid.

5 0

3 years ago